Hydraulic boom extension assembly



D. BRYAN HYDRAULIC BOOM EXTENSION ASSEMBLY May 12, 19 59 2 Sheets-Sheet Filed Jan'. 23. 1956 INVENTOR.

fl a m W M w M 1 p Q D. L. BRYAN HYDRAULIC BOOM EXTENSION ASSEMBLY May 12, 1959 2 Sheets-Sheet 2 Filed Jan. 25, 1 95a i United States Patent This invention relates to improvements in loadhoistdevices of the kind disclosed in Raymond O.Pitman et al. Patents No.2,559,733 and No. 2,717,701, and tnoreparticularly to the boom structure. of such devices, the primary object being. to provide novel actuating structure for extensiblebooms. M

It is the most important objectof the present invention to provide a hydraulic boom extension assembly 'thatrinclucles a pair of opposed, double-acting pistons reciprocable within a common cylinder, the latter of which is itself mounted for free movement with respect to the pistons and the extensible sections of the boom.

Another important object of the present invention is to provide hydraulic power means of the aforementioned character that is housed within a pair of relatively telescoped extensibleboom sections and having each piston connected with one of the sections to the end that the latter aremoved relatively upon actuation of the pistons within their cylinder.

A further object of the present invention is to mount a hydraulic, double-acting piston and cylinder assembly within a boom by connection of each of the pistons to one of the sections and by slidably supporting the cylinder within one of the sections for reciprocable movement with respect thereto.

A still further objectof this invention is to provide a hydraulic assembly wherein is included means for directing hydraulic pressure between the pistons through one of the stems therefor, as well as to the outer faces of the two pistons through passage means in the said stem and a by-pass interconnecting the two opposed chambers of the cylinder.

Other objects include important details of construction to be made clear or become apparent as the following specification progresses, reference being had to the accompanying drawings, wherein:

Figure 1 is a longitudinal, cross-sectional view through a hydraulic boom extension assembly made pursuant to my present invention taken on irregular line I--I of Fig. 2. Fig. 2 is a fragmentary, end elevational view thereof. Fig. 3 is a fragmentary, side elevational view on a reduced scale of a load-hoisting device in the nature of that disclosed by the aforementioned patents and having an extensible boom structure embodying the hydraulic assembly of the instant invention.

Fig. 4 is an enlarged, fragmentary, longitudinal, crosssectional view through the boom structure shown in Fig. 3 and showing in elevation the hydraulic assembly illustrated in Figs. 1 and 2.

Fig. 5 is a transverse, cross-sectional view taken on line V--V of Fig. 4; and

Fig. 6 is a cross-sectional view taken on line VI-VI of Fig. 4.

The disclosures of the patents above-identified, are incorporated herein by reference for a complete understanding of the type of load-lifting device chosen for illustration in Fig. 3 of the drawings and with which the Patented May 12', 1959 ice hydraulic boom extension assembly of the instant in vention adapted to be used.

Boom structure 10 includes an outermost, elongated, tubular section 12 and an inner elongated, tubular section 14 telescoped within the section 12 for longitudinal reciprocable movement with respect thereto. s

The boom section 12 is mounted on an uprightstandard 16 through themedium of sheave means 18 rigid to the standard 16. A pivot 20 permits swinging movement ofthe boom structure 10 on a horizontal axis and standard 16 itself is mounted for rotation on its vertical axis for horizontal swinging movement of the boom structure 10. Such horizontal movement is controlled by opposed hydraulic piston and cylinder units operably coupled through'cable means with sheave 18, one of such units beingseen in Fig. 3 and designated bythe numeral 22. Vertical swinging of the boom structure 10 is controlled by cable means 24 that is in turn operably connected with power means, not shown. r

A winch is coupled with lifting :cable 28 that extends through thetubula r standard16 beneath a pulley 30 on pivot 20, thence through the boom structure 10 and over a pulley 32 mounted at the outermostend of the inner boom structure 14. Section 14 is provided with guide means34 for the cable28 and with a roller 36 at its innermost endtherewithin disposed in rolling contact with the innermost face of the uppermost wall of booni section 12. Aslot or opening 38 in the section 14, clears the roller-36. Another roller 40 carried bythe section 12 at the outermost end thereof, is in rolling contact with the lower face of section 14. Consequently, rollers 36 and 40 provide anti-friction means for freedom of movement of the section 14 as a load on the cable 28 tends to tip the outer end of section 14 downwardly and the inner end thereof upwardly toward the upper surface ofsection'12. i

The power meansforming the subject matter of the instant invention forreciprocating the section 14 with respect to section 12, is hydraulically actuated and; to this end, there is provided an elongated cylinder 42. that may be formed in two sections as seen inFig. 1 interconnected by a tubular plug 44 serving as a stop for a pair of opposed pistons 46 and 48.

Pistons 46 and 48 have elongated stems or rods 50 and 52 respectively secured rigidly thereto and extending in opposite directions beyond the ends of the cylinder 42 through glands 54 and 56 that are in turn held in place by retainer rings as shown in Fig. 1.

Rod 50 has a crosshead 58 on the outermost end thereof received by opposed tubular journals 60 secured rigidly to the section 12 adjacent the innermost end of the latter.

The rod 52 is provided with a tubular crosshead 62 that is received by a stub shaft 64 traversing the section 14 and rigidly secured to the latter.

Cylinder 42 is freely movable with respect to pistons 46 and 48 and with respect to the boom structure 10 and is, therefore, slidably supported by the inner section 14 through the medium of a pedestal 66.

A fluid passage 68 extending longitudinally through the rod 50 and its crosshead 58, communicates with the cylinder 42 between the pistons 46 and 48. A second fluid passage 70 within the rod 50 has a lateral discharge end 72 communicating with the cylinder 42 between the piston 46 and the gland 54. A by-pass 74 interconnects chambers 76 and 78 of the cylinder 42. Hydraulic fluid is directed to and from the passages 68 and 70 through flexible hoses 80 and 82 respectively emanating from a suitable source of fluid pressure not shown.

In operation, when hydraulic pressure is directed into the cylinder 42 through hose 80 and passage 68, section 14 is extended outwardly as the cylinder 42and the piston 48 move toward the outermost end of the section 2,886,005 .r a I a 1g, and duringsueh movement of the gland 54 toward the piston 46 within the chamber 76 flows to the hose 82 by way of passage 70. As soon as the gland'54 engages the piston 46 thereby limiting the extent of movem nt at y in q 2,: th fluid p q rc b ween h pistons 46 and 48 causes the .piston4 8 tomovefalong the cyl nder n a d-t e and 56- Fluid 'isIfo'rc Lfr the chambe 8 hrough the y-nass 7 the e into the zchaniber76 and to hose 82 by way of lateral extension 72 and passage 70. p

Manifiestly, the section 1 4. is retracted by reversing the flow of hydraulic fluid and as such fluid is forced into the-chamber 76 th ugh hose'82, passag 70 nd l eral extension 72, cylinder \42 isfirstretracted toward the .c qssh a 5.8, t e gland 5. ear g g i st th p ston 48 and moyingthe latter therewith toward the piston until the 61. 1 4 str es he-Piston 46 A so n a he piston 6 str ke m nki f: .I .Cm g flu d will flow n o chamber 7 y. w y f.hyp s 7 her y m ingflthe n rs tmflfisi ar ly ithrcspe o t e y in er 42 unt tstrikesthe st p 4 i The by-pass 74. remains in communication with the chambers 76 and 78 even when the pistonsldand arei engagement with the glands 54 and 5.6 respectively by virtue of the lprovision of annular grooves 84 .86 in. P n 6. and 48 sp ti e y, n dur ng trac ion fluid escapes from between the, pistons 46 and. 48 byway P ssa e It is seen from theforegoing tha ttn aximum extension Qi the s ct n 141snr videdt mu h u e iqf a r l tiv ly short, lightwei ht hydraulic piston and cylinder assembly. The oppo ed, pis n 4 5-, and .8. mult ply he; et ec mo ement Qt he c o .4 an h ugh s f. amp Mal, t adjust; theb Qm 10 w t nq i n th pulley 2 at an des red locati nab ye a load to be. i d, through was acable 28- Har n hus de cr b d, the. in ent n. at s claimed a ne -an e ire o -QSQQ s by Let s. P n

1 Hydraulic structure for reciprocating a of tele; scoped t bes, sai structure, compr sing a flqati g eylinden;- a pa ro opp sed pis ons with nthe. cy nde a 'n tqn od xte d n -ou wardly vf om e ch p s q espe ti e yr ne-Qt t e n sha n firstP s a-g -flowof a cqn Ql w thm he hydraul c sys it. is; possibl l glands', one of said rods having 'a first passage ccmmumpassage communicating with said cylinder between the pistons, and a second passage within said rod for flow of fluid into and out of the cylinder, said second passage communicating'with the cylinder between one of the pistons and that end of the cylinder proximal to said one rod, said one of the pistons being mounted on said one rod; stop means within said cylinder and disposed between said pistons for' limiting the movement thereof; and a bywpass line communicating ,with said secondtpassage andinterconnecti'ng the oppo'site'ends "of the cylinder.

- 2; Hydraulic structure for i'ecipr'oeating-;apair ofitclescoped tubes, said structure comprisinga painof tubular sections; glands closing each section at one end thereof; a tubular-plug joining said sections at theopposite ends thereof whereby to form an elongated cylinder, saidplug being disposed centrally thereoffa pair of opposed pistons within said cylinder, said plug being between said pistons and forming a stop therefor whereby said pistons are maintainedin spaced relationship; a piston rod extending outwardly from each piston respectively and through; said eating with said cylinder between the pistons,,an c n l pass ge n a one rod for flow Qfffluidintojand out of the cylinder; said second passage communicating with the cylinder between lone of the" pistons and that end of the cylinder proximal to, said; one rod, said one of the pistons being mounted on said one rod; andja bypass l-ineeon1municating withsaid second passage and interconnecting the opposite ends of the cylinder,

ReferencesWCited in the. file of thisi patent I y "STATES PATENTS Sibley-n. Mar-j 6119,00 1,518,788 Hanna v t..v 'Dec. 9, 19.24

- 2,365,167 Billings D c. 19,1944 2,393,503 Bosomworth V Ian 2 2, 1946 2,478,790, Stephens, Aug;- 9,.1914'9' 25,87,893 Pridy- M3 4, 11 9,52 2,684,159 Oldenkaimp July 20,1954 2,688,313 Bauer l Septi 2,}1954 1,746,612 Wirz V May 22, 195,6

7 FOREIGN PATENTS I i i 5 85,38'8- G rma y '-s-- v v Qctifi 1933 

